Overview

Definition:
-Pediatric achalasia is a rare, idiopathic esophageal motility disorder characterized by the absence of peristalsis in the esophageal body and impaired relaxation of the lower esophageal sphincter (LES)
-This leads to progressive dysphagia, regurgitation, and malnutrition
-Heller myotomy is a surgical procedure involving longitudinal myotomy of the esophageal muscles at the gastroesophageal junction to relieve the obstruction caused by the hypertensive and non-relaxing LES.
Epidemiology:
-Achalasia is uncommon in children, accounting for approximately 1-5% of all achalasia cases
-Incidence varies, but it is estimated to be around 0.3-0.5 per 100,000 children per year
-There is no clear gender predilection, and it can affect infants to adolescents
-Primary (idiopathic) achalasia is most common, though secondary achalasia can occur in association with certain rare conditions like Allgrove syndrome (triple A syndrome).
Clinical Significance:
-Undiagnosed or inadequately treated pediatric achalasia can lead to significant long-term morbidity including severe malnutrition, failure to thrive, recurrent aspiration pneumonia, esophageal dilation, and an increased risk of esophageal squamous cell carcinoma in adulthood, though this risk is lower in pediatric-onset disease
-Early diagnosis and effective management are crucial for improving quality of life and preventing complications.

Clinical Presentation

Symptoms:
-Difficulty swallowing (dysphagia) to solids and liquids, often progressive
-Regurgitation of undigested food, especially when lying down
-Chest pain, described as pressure or burning
-Weight loss and poor growth
-Recurrent pneumonia or coughing spells due to aspiration
-Heartburn, often not relieved by antacids, due to retained food
-Vomiting, particularly of retained food
-In infants, irritability, poor feeding, and failure to thrive.
Signs:
-Poor nutritional status, evidenced by low weight-for-age
-Palpable dilated esophagus or undigested food in the pharynx in severe cases
-Signs of aspiration pneumonia (fever, tachypnea, crackles on auscultation)
-Possible halitosis due to retained food
-Abdominal distension in infants due to aerophagia or gastric distension.
Diagnostic Criteria:
-Diagnosis is typically based on a combination of symptom history, endoscopic findings, and functional testing
-While specific diagnostic criteria are less formalized for pediatric achalasia than for adults, the presence of a non-peristaltic esophagus with a poorly relaxing LES on manometry is definitive
-Esophageal manometry is considered the gold standard for diagnosis.

Diagnostic Approach

History Taking:
-Detailed history focusing on the nature, duration, and progression of dysphagia
-Distinguishing between difficulty with solids vs
-liquids
-Characterization of regurgitation (timing, content)
-Episodes of aspiration, cough, or pneumonia
-Weight loss and impact on growth
-Previous medical history, including infections or genetic syndromes
-Family history of achalasia or other gastrointestinal disorders
-Red flags include rapid onset of severe dysphagia, significant weight loss, and signs of aspiration.
Physical Examination:
-General assessment of nutritional status and hydration
-Thorough cardiopulmonary examination to detect signs of aspiration pneumonia
-Abdominal examination for distension or tenderness
-Oropharyngeal examination to assess for food residue or gag reflex
-Neurological examination to rule out underlying neuromuscular disorders.
Investigations:
-Barium swallow: may show dilated esophagus, a dilated stomach with air-fluid level, tapering of the distal esophagus resembling a "bird's beak" or "rat tail" appearance
-Esophageal manometry: the gold standard, demonstrating absence of peristalsis in the esophageal body and incomplete relaxation of the LES with swallows, and elevated LES resting pressure
-Upper endoscopy (esophagogastroduodenoscopy - EGD): to rule out mechanical obstruction (e.g., stricture, tumor) and to assess for esophagitis or retained food
-may show retained food, dilated esophagus, and a tight gastroesophageal junction
-Esophageal pH monitoring and impedance: may be used to assess for reflux, though less common as a primary diagnostic tool for achalasia.
Differential Diagnosis:
-Eosinophilic esophagitis: dysphagia, chest pain, often responds to steroids
-Diffuse esophageal spasm: intermittent dysphagia and chest pain with peristalsis present but abnormal
-Achalasia variant
-Strictures (benign or malignant): history of reflux, caustic ingestion, radiation therapy
-Gastric outlet obstruction: vomiting of undigested food, but LES relaxes
-Neuromuscular disorders affecting swallowing: stroke, myasthenia gravis
-Allergic reactions leading to esophageal edema.

Management

Initial Management:
-Nutritional support is paramount, especially in malnourished children
-This may involve high-calorie, low-residue diets, and if necessary, nasogastric or gastrostomy tube feeding
-Management aims to reduce LES pressure and improve esophageal emptying.
Medical Management:
-Pharmacological treatment is generally less effective and often temporary in pediatric achalasia
-Calcium channel blockers (e.g., nifedipine) and nitrates (e.g., isosorbide mononitrate) can be used to relax the LES, but their efficacy is limited and long-term results are often poor in children
-Botulinum toxin injection into the LES can provide temporary relief but is less durable than surgical or pneumatic dilation.
Surgical Management:
-Heller myotomy is the definitive treatment for pediatric achalasia
-It involves surgically dividing the circular muscle fibers of the LES and a portion of the longitudinal muscle fibers of the distal esophagus
-Laparoscopic Heller myotomy (LHM) is the preferred approach due to its minimally invasive nature, shorter recovery time, and reduced postoperative pain
-An anti-reflux procedure, such as a partial fundoplication (e.g., Dor or Toupet), is typically performed concurrently to prevent gastroesophageal reflux (GERD), which is a common complication post-myotomy
-Indications for surgery include failure of or intolerance to non-surgical treatments, or as a primary treatment in most pediatric cases
-The procedure aims to relieve the obstruction by cutting the hypertrophied LES muscles.
Supportive Care:
-Postoperative care includes pain management, monitoring for complications (such as bleeding, infection, or perforation), and gradual reintroduction of oral feeding
-Nutritional support may be continued as needed
-Long-term follow-up is essential to monitor for symptom recurrence, reflux, and the development of esophageal dilation or complications.

Complications

Early Complications:
-Bleeding from the myotomy site
-Esophageal or gastric perforation during myotomy or fundoplication
-Injury to adjacent organs (e.g., spleen, vagus nerve)
-Pneumothorax or atelectasis
-Anastomotic leak (rare if no actual anastomosis).
Late Complications:
-Gastroesophageal reflux disease (GERD) is the most common late complication, occurring in 10-40% of patients, hence the routine performance of an anti-reflux procedure
-Esophageal stricture at the myotomy site
-Recurrence of achalasia symptoms if myotomy is incomplete or too short
-Esophageal dilation, which may not reverse even after successful myotomy
-Increased risk of esophageal squamous cell carcinoma in the long term, though this risk is significantly lower in pediatric-onset achalasia compared to adult-onset.
Prevention Strategies:
-Meticulous surgical technique during Heller myotomy, ensuring adequate length of myotomy and preservation of surrounding structures
-Careful selection and performance of an appropriate anti-reflux procedure concurrently with myotomy
-Postoperative dietary modifications and lifestyle advice to minimize reflux
-Regular endoscopic surveillance for premalignant changes in long-standing achalasia cases.

Prognosis

Factors Affecting Prognosis:
-Age at diagnosis (earlier diagnosis may lead to better outcomes), severity of esophageal dilation at diagnosis, technical success of the myotomy and anti-reflux procedure, and adherence to postoperative management and follow-up
-The presence of pre-existing significant esophageal dilation or stasis can impact long-term outcomes.
Outcomes:
-Heller myotomy, especially when performed laparoscopically with an anti-reflux procedure, offers excellent symptom relief and improved quality of life in most pediatric patients
-Success rates are generally reported to be high, with significant improvement in dysphagia and regurgitation
-However, a small percentage may experience persistent or recurrent symptoms, often related to GERD or incomplete myotomy.
Follow Up:
-Lifelong follow-up is recommended
-This typically involves regular clinical assessments to monitor for symptom recurrence or progression
-Endoscopic evaluations may be performed periodically, especially in patients with long-standing disease or those at risk for dysplasia or malignancy
-Monitoring for GERD and its sequelae is crucial.

Key Points

Exam Focus:
-Heller myotomy is the surgical gold standard for pediatric achalasia, aiming to disrupt the hypertensive, non-relaxing LES
-Laparoscopic approach with concurrent anti-reflux procedure is standard
-Manometry is diagnostic
-Differential diagnosis includes eosinophilic esophagitis and diffuse esophageal spasm
-GERD is the most common complication.
Clinical Pearls:
-Always consider achalasia in a child with progressive dysphagia to solids and liquids, and regurgitation
-Barium swallow is a good initial imaging study, but manometry confirms the diagnosis
-A concomitant anti-reflux procedure is vital after myotomy to mitigate significant GERD risk
-Differentiate symptoms of achalasia from GERD
-Prompt surgical intervention is often preferred over less durable medical or endoscopic treatments in children.
Common Mistakes:
-Failure to perform an anti-reflux procedure alongside Heller myotomy, leading to problematic GERD
-Inadequate length of myotomy, resulting in persistent obstruction
-Misinterpreting barium swallow findings and delaying manometry
-Overlooking achalasia in infants presenting with poor feeding and failure to thrive
-Not considering secondary causes of achalasia in the rare instances.